Patent GB-497189-A (GB)
Title: Interlocked duplex broaching machine
IPC: B23Q5/06
Filed: 1938-03-22
Abstract: 497,189. Broaching - machines. LAPOINTE MACHINE TOOL CO., Ltd. (Lapointe Machine Tool Co.) March 22, 1938, No. 8798. [Class 83 (iii)] A duplex broaching machine having a pair of alternately-acting rams A, B has a workslide movable transversely to operative relation with either ram and work clamping means carried by the slide, and interlocking controls are provided between the rams, the slide, and the clamping means so that neither the rams nor the slide can be moved until the work is clamped. The rams are operated by hydraulic cylinders 22, 23 supplied from a reversible pump P controlled through rack-and-pinion gearing 26 from a hand lever 30 which is also connected to a main control piston 31. The rams A, B carry stops 37, 42 respectively which at the end of the downward working stroke coact with collars or rods 33, 38, to return the lever 30 to its neutral position wherein there is no flow from the pump. The lower ends of the ram cylinders are connected by a pipe 43 having a back pressure valve 43a. The control cylinder 32 is supplied by an auxiliary pump P<1> delivering through a solenoid controlled valve V whose rate of movement is controlled by a needle valve 46. The work slide 50 is operated by a movable cylinder 51 sliding over a fixed piston rod 52. The piston rod is hollow and passes oil to opposite sides of the fixed piston 52a from lines 53, 54 supplied by a pump <p2>, delivering through a needle valve 57 to a valve V<1>. Back pressure is provided by a valve 58. The valve V<1> is operated by a hand lever 60 which is locked in one position or other by a solenoidoperated plunger 61. The two ends of the work cylinder are connected through valves 64, 65 to another valve V<2> operated by a hand lever 70 and connected to a work clamping cylinder 68, the work being clamped when the piston 69 is in its lowered position. The valve V<2>, cylinder 68, and work clamps, all move with the work slide 50. At opposite ends of its travel the work slide closes normally open switches 80, 81 and other switches 82, 83 are closed by cam pieces on the rams which operate when one or other of the rams is in raised, position. The switch 82 is of double-pole type one arm being in circuit with an arm of double pole switch 81 and with a coil 86 controlling a plunger coacting with a plate 88 on lever 70. Another switch 94 is closed only when the work is clamped. Starting from the loading position of Fig. 1, the operator, after loading, moves handle 70 to the Fig. 2 position thus reversing the connections to cylinder 68 and lowering piston 69 to clamp the work and close 'switch 94. A manual switch 92 is then closed, completing the circuit of solenoid 62 and switch 94 and releasing lever 60 which can be operated to shift valve V<1> and move the work slide to the left so closing switch 80 and opening switch 81. The opening of switch 81 de-energizes the solenoid 86 so that handle 70, Fig. 2, is now locked against unclamping movement. Also the closing of switch 80 completes a circuit of valve V, thus supplying oil to cylinder 32 and operating lever 30 so that the pump delivers to the upper end of cylinder 22 and moves ram A downwards. This breaks the circuit of valve V which returns to neutral. At the end of the downstroke of the ram A the handle 30 is returned to neutral by the stop mechanism while the ram B closes switch 83. The switch 92 is now again closed to release handle 60 and valve V is shifted to move the work slide to the right. When switch 81 is closed, the reverse circuit of valve V is completed and control cylinder moves the lever 30 to supply oil to the upper end of cylinder 23. When this movement of ram B begins solenoid 62 is de-energized and lever 60 is locked. As soon as ram A reaches its initial position the switch 92 is closed and plunger 86 thus withdrawn so that lever 70 may be operated to unclamp the work and open switch 94. The parts are now in the initial, Fig. 1, position.